General Electric Company

Ronald B Bailey

Thomas D Stitt

Herbert J Brown

Myron L Smith

Edgar T Balch

Joseph A Laukaitis

Dennis Francis Williamson

Roger D Huczko

Ajith Kuttannair Kumar

Eric J Wildi

Dimitrios Ioannidis

Ronald F Griebel

Stephen T Radack, Jr

Wayne Alexander Kennedy

Vinod Kumar Singh

David L Plette

An electrically powered vehicle includes an inverter mounted in the vehicle, the inverter having a plurality of high power IGBT modules for converting DC power to AC power for application to a plurality of AC electric motors connected in driving relationship to wheels on the vehicle. Each of the IGBT modules is mounted in thermal transfer relationship to an electrically isolated base plate and each base plate has a plurality of closely spaced, parallel slots formed across one surface with a plurality of fins fitted into the slots and extending from the base plate. The system includes apparatus for mounting the IGBT modules to a wall separating an electronics compartment from an air supply and air exhaust compartment. Air from an air supply plenum in the air supply compartment is directed into the fins extending from the IGBT base plate and exhaust through an exhaust conduit. The vehicle includes a blower to force air to flow through the fins extending from the base plate.

High power inverter air cooling

An electrical power system includes an inverter having a plurality of insulated gate bipolar transistors (IGBTs) and capacitors for converting DC power to AC power and at least one power bus bar including an interconnecting bus bar and a plurality of extension bus bars. The area between the conductors of the interconnecting bus bar and the extension bus bars is minimized to reduce the inductance between the IGBTs and the capacitors. The extension bus bars are each coupled to the interconnecting bus bar and a respective one of the IGBTs and capacitors. An IGBT can be removed from the inverter without removing the interconnecting bus bar or any other IGBT. The capacitors can be positioned at ninety degree angles with respect to the interconnecting bus bar. In one embodiment, the IGBTs are additionally positioned at ninety degree angles with respect to the interconnecting bus bar. In an alternate embodiment, the IGBTs are positioned parallel with respect to the interconnecting bus bar.

Modular bus bar and switch assembly for traction inverter

For responding to a shorted gate in a gate turnoff thyristor the gate electrode of which is connected by means of a controllable switch to a control voltage terminal having a negative potential with respect to the cathode potential of the thyristor, the controllable switch being arranged to conduct negative gate current in response to a thyristor turnoff command, voltage comparing means is coupled to the controllable switch for detecting when the switch is conducting negative gate current of relatively high magnitude, timing means is active for a predetermined interval following the start of said thyristor turnoff command, and logic means is operative to cause the switch to stop conducting negative gate current if the voltage comparing means detects high gate current at the end of such interval.

Gate turnoff thyristor control circuit with shorted gate detection

A plurality of high power semiconductor devices are connected in circuit with at least one electric traction motor for controlling electric power to the motor. The semiconductor devices are each thermally connected between a pair of generally hollow heat sinks adapted for passing cooling air therethrough for extracting heat therefrom. An anode terminal of the devices is coupled to one of the heat sinks of a pair and a cathode terminal of the devices is connected to the other heat sink of the pair. Each of the heat sinks are mounted in a cantilever fashion to a common air plenum forming one wall of an electrical circuit area of a vehicle. The distal ends of the heat sinks of a pair are coupled together by an air flow conduit thus forming a continuous air passage through the pair of heat sinks which begins and ends at the surface containing the air supply plenum. One end of one of the pair of heat sinks, preferably the heat sink coupled to the cathode terminal, is connected to an exhaust conduit. Cooling air is then directed into the end of the other heat sink, circulating through the one heat sink and out through the exhaust conduit. In this manner, the cooling air is held in a closed path extending into the electrical circuit area so that contaminants are not deposited on the electrical components.

High power AC traction inverter cooling

Flashover protection is provided for a locomotive propulsion system including a plurality of d-c traction motors each having a commutator subject to flashovers, a traction alternator having armature and field windings and a rotor driven by a prime mover, a controllable source of excitation current connected to the alternator field, and means including an electric power rectifier for connecting the alternator to the motor commutators. It comprises means for producing a fault signal whenever a flashover occurs in any motor, a solid-state controllable electric valve connected between the excitation current source and the alternator field and having alternative conducting and non-conducting states, and means for changing the valve from conducting to non-conducting states in response to a fault signal being produced, whereupon the magnitude of excitation current in the alternator field is rapidly reduced toward zero and the alternator's output current is correspondingly decreased whenever a flashover occurs.

Automatic flashover protection for locomotive traction motors

A power supply has a stack formed by a first bus plate, a gate take off (GTO) thyristor, a second bus plate, a bypass diode and a third bus plate all mounted to a heat sink by a single clamp, with the anode of the thyristor closest to the heat sink. Preferably, the bus plates are sized and of a material to provide local thermal storage. The heat sink then can be sized to handle only the average heat dissipation requirements, rather than the peak requirements, and the total power supply can be very compact.

GTO module with piggyback bypass diode

For connecting the d-c terminals of a voltage-source inverter to a direct current (d-c) power source, a d-c link capacitor is connected directly between the d-c terminals, a line capacitor is connected in parallel with the d-c link capacitor, and a series inductor is connected between the line capacitor and the source. A dynamic brake resistor and an electric power chopper are connected in series with one another across the line capacitor. Between the two capacitors, no inductance is provided but a resistor is inserted in the braking current path during electrical braking operation of the inverter.

Power conversion system including an improved filter for attenuating

A propulsion system for an electrically driven traction vehicle includes a chopper, a d-c traction motor, and means effective when the system is operating in a motoring mode for connecting the chopper in series with the armature and the field windings of the motor to a d-c electric power source that includes a filter capacitor. Cyclically operative means provides periodic gating signals for alternately turning on and turning off the chopper, and it can be smoothly changed from a constant frequency, variable pulse width mode to a variable frequency, constant (minimum) off time mode so as to vary the 'duty factor' of the chopper over a wide range extending up to 100 percent on time. Brake set up means is operative in response to a motoring-to-braking command for reconnecting the chopper in parallel with the motor and the filter capacitor and for reversing the polarity of the connection of the series field winding relative to the armature. In response to this operation of the brake set up means, current in the field of the motor is momentarily boosted, and an extended chopper turn on signal having a duration substantially longer than that of the aforesaid periodic gating signals is supplied to the chopper to ensure that it turns on and conducts armature current to begin the braking mode of operation even if the command happens to take place at low speeds when the electromotive force of the motor is correspondingly low.

Chopper type propulsion system with low speed electrical braking

Apparatus for controlling the voltage on a commutating capacitor in a thyristor time ratio control power circuit whereby the energy stored in the capacitor may be continuously adjusted to a magnitude required for commutation so that the size of the commutating circuit can be significantly reduced. An inductive circuit is provided in a charging current path for the capacitor so that the capacitor can be charged above available source voltage by capacitive/inductive action. A controllable switch connected in parallel with the inductive circuit provides a short-circuit path for terminating charging of the capacitor. A logic circuit monitors capacitor voltage, source voltage and load current and closes the controllable switch when the capacitor voltage reaches a magnitude established by the logic circuit as sufficient to commutate the measured magnitude of load current.

Chopper with adaptive energy commutation

A pulse shaping and amplifying circuit is formed by connecting a capacitor in series with the primary winding of a pulse transformer, connecting normally open switching means in parallel with the capacitor and primary winding, and connecting this parallel combination through a series inductor to a source of d-c control power, whereby the capacitor accumulates a charge from the control power source and then, during periods when the switching means is closed, discharges through the switching means and the primary winding. During its closed periods the switching means also conducts current from the control power source through the inductor, but when the switching means is opened the current in the inductor is transferred to the capacitor and the primary winding and thereby assists recharging of the capacitor. The pulse transformer is provided with at least one secondary winding which is connected to a load circuit by a full wave rectifier means comprising a first diode poled to conduct load current when capacitor discharge current is flowing in the primary winding and serially interconnected second and third diodes poled to conduct load current when capacitor charging current is flowing in the primary winding. Another capacitor is connected in series with one of the second and third diodes across the load circuit, whereby it ensures continuous load current after the first half cycle of operation of the pulse shaping circuit if the closed periods of the switching means recur at a sufficiently high frequency.

Electric pulse shaping circuit

Apparatus for providing firing signals to a phase controlled rectifier circuit at a time at which valves in the rectifier circuit are forward biased without the need for providing continuous firing signals. The apparatus monitors the voltage applied across the rectifier valves and provides a signal when a valve is forward biased. This signal is applid to a gating circuit which determines whether a normal phase control firing command was initiated prior to the time the valve became forward biased. If such a command was initiated, the gating circuit passes the signal to a valve firing circuit which provides firing signals to the rectifier circuit. If the firing command was not previously initiated, the signal is inhibited and firing signals are subsequently applied to the rectifier circuit upon receipt of a firing command.

Control logic for a phase controlled rectifier system

Apparatus for increasing the available regenerative braking energy and for enabling low current control without frequency variation in a time-ratio controlled main thyristor power circuit for a direct current traction motor. A variable impedance element is serially inserted in a motor armature free-wheeling current path between a free-wheeling diode and the motor armature, the variable impedance element preferably comprising a power resistor and parallel connected thyristor. During electrical regenerative braking the thyristor is used to modulate the power resistor to thereby present a continuously variable impedance in the armature current path. During motoring at very low speeds the thyristor can be operated to modulate the power resistor and thus reduce the minimum controllable level of motor current normally limited to commutation current level without the necessity of reducing the main thyristor operating frequency. The thyristor is gated on by conventional means but is gated off by triggering the commutation circuit of the main thyristor, thus eliminating the need for a separate commutating circuit for the thyristor.

Direct current motor chopper propulsion system

A method and control system for minimizing peak current levels in a direct current traction motor drive system in which the traction motor is powered by periodic current pulses metered from a direct current source by a controllable switch. The control system includes apparatus for comparing actual motor current to commanded motor current and for controlling the duty factor of the controllable switch in a manner tending to minimize any difference between actual and commanded currents. The control system further includes apparatus for changing the repetition rate of the current pulses in response to the magnitude of current in the motor, without effecting the commanded duty factor of the controllable switch, so that the ripple currents which are inversely related to repetition rate are reduced as average motor current is increased to thereby maintain total peak current levels within predetermined limits.

Multiple frequency chopper control

Method and apparatus for effecting control of a complementary impulse commutated inverter to enable start-stop operation without power removal and to avoid start-up failures caused by inductive load flux saturation. The invention utilizes a gating logic circuit to always start inverter operation by gating a first predetermined switching element. The gating logic circuit responds to a stop command by terminating operation in a half-cycle in which the first predetermined switching element is not carrying load circuit. In one embodiment upon receipt of a stop command the gating logic circuit terminates inverter operation by applying a last gating signal to the first predetermined switching element, the last gating signal having a time duration less than that required after receipt of a gating signal for current reversal in the inductive load. The last gating pulse is effective to commutate the conducting switching element and current reversal in the load is effective to commutate the first predetermined switching element.

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Erie, PA, United States of America

Ronald B Bailey